Kinetic model of gas phase polymerization of 1,3-butadiene catalyzed by supported rare earth coordination system

Gas phase polymerization of 1,3-butadiene (Bd) catalyzed by supported rare earth coordination system is studied and a new kinetic model is proposed. Four elementary reactions or processes: the process of exposure and activation of potential active catalytic center, propagation, deactivation and chain transfer reaction to alkyl aluminum, are considered in this model. Some important parameters, such as monomer-consuming rate, are well expressed as the functions of macroscopic polymerization conditions such as pressure, temperature, and duration. The model can simulate the whole polymerization procedure satisfactorily.     

Hydrochlorination of δ2-1,3-oxazolines and 1,3-oxazolidines

The compounds 2-(ethoxycarbonylmethyl)-²-l,3-oxazoline and 1-methyl-2-(methoxycarbonylmethylene)-1,3-oxazolidine are hydrochlorinated at the C=N or C= C bond, respectively, with subsequent opening of the oxazolidine ring. Depending on the reaction conditions, this occurs regioselectively to form various products.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 5, pp. 684–686, May, 1992     

1,3λ3-Azaarsinine

The title compounds are available for the first time by O/As-exchangereaction of 1,3λ³-azapyryliumsalts with As(SiMe₃)₃.     

Blue,green,red upconversion luminescence and optical characteristics of rare earth doped rare earth oxide and oxysulfide

The cold isostatic press pretreatment process was adopted to prepare fine rare earth oxysulfide up-conversion phosphors with spherical shape, narrow size distribution and high luminescence efficiency. The upconversion optical characteristics and brightness of the blue (Y2O2SYb,Tm), green (Y2O2S: Yb,Er), red (Y2O3Yb,Er) emitter were also investigated, and a novel method was successfully developed for the brightness measurement of upconversion luminescence (UPL). It is shown that a white color can be obtained by the appropriate mixture of these primary blue, green and red emissions components. The Er3 ions exhibit different upconversion mechanism in Y2O2S and Y2O3 host materials. The rare earth oxysulfide is an efficient upconversion matrix. The UPL brightness of Y2O2S: Yb,Er is 6.5 times higher than that of Y2O3: Yb,Er, and Y2O2S: Yb,Er shows UPL brightness of 1100 cd/m2 under 5.56 W/cm2 power density using a 980 nm laser diode.     

Synthesis of Some Potential Antiangiogenic 1,3-Dihydro-1,3-dioxo-2H-isoindole Derivatives

The proliferation, invasion and metastasis of malignant tumors are closely related withangiogenesis induced by tumor cells. Blocking tumor-induced angiogenesis is anefficient strategy to prevent and cure cancer1. Recent studies indicated that theangiogenic process depends on vascular endothelial cell migration and invasion, whichregulated by αvβ3 receptor2. The receptor and extracellular matrix can recognize eachother through Arg-Gly-Asp (RGD) consensus sequence found in matrix ligands…     

Metal derivatives of 1,3-bis(2-pyridyl)-1,3-propanedione and N,N′-dimethyl-1,3-bis(2-pyridyl)-1,3-propanedione

Complexes of transition metal ions with the oxygen-nitrogen containing ligand 1,3-bis(2-pyridyl)-1,3-propanedione (bpypH) have been synthesized. These present stoichiometries which do not conform with the usual tendency manifested by β-diketones, since molecular formulas with the composition M(bpyp)X are found. A nitrogen methylated ligand N,N′-dimethyl-1,3-bis(2-pyridyl)-1,3-propanedione methyl sulphate [dimebpypH] (MeSO₄)₂ has also been synthesized and its complexes with transition metal ions studied. The stoichiometries now, resemble those of typical β-diketones, namely [dimepyp]₂MX₄ with four anions because of the dicationic nature of the original ligand. This, together with IR evidence suggests a dual type of coordination by bpip via the β-diketone and the pyridyl moieties.     

1,3-Diphosphetane-2,4-diyles--Cryptocarbenes?

1,3-Diphosphetane-2,4-diyles ( A ) possess a diradical molecular structure. Experimental studies reveal interconversions of different valence isomers of the diradicals. As a consequence of the facile thermal ring opening of 1,3-diphosphetane-2.4-diyles A , we obtained crypto-phosphinocarbenes ( B ), confirmed by the results of intramolecular rearrangements as well as reactions with multiple bonded systems. A new range of five- and six-membered phosphorus heterocycles are isolated, including transition-metal complexes. The mechanism for the ring-expansion are predicted by quantum chemical calculations.     

Nanostructural oxide “memory” of rare earth molybdates

The structural aspects of the acid-base interaction in the course of formation of molybdates in the binary systems Ln₂O₃-MoO₃ have been considered. The structures of rare earth molybdates inherit infinite bands of {[LnO _n ]-[LnO _n ]} dimers from the structures of Ln₂O₃ oxides. The nanostructural oxide “memory” of molybdates implies that the dimers in these bands retain approximately nanometer sizes and predominant mutual orientation despite the fact that, as the Mo formula content increases, the types of polyhedra in the dimers change and the contacts between dimers and, eventually, between the polyhedra in these dimers are lost.     

1,3-丙二醇制备研究进展

1,3丙二醇（1,3-PDO）是一种重要的化工原料,可以作为溶剂、抗冻剂、增塑剂、乳化剂、防腐剂、洗涤剂和润滑剂等[1],在食品、医药、化妆品和有机合成中有着重要应用.此外,1,3-PDO还可以作为聚酯、聚醚和聚氨酯的单体．     

Reactions of enamines with fluorinated acyl chlorides----Synthesis of fluorinated 1,3-diketones and 1,3-keto-aldehydes

The reactions of enamines (1a-b,4,6) with fluorinated acyl chlorides (2a-d) produced fluorinated 1,3-diketones (3a-f) and 1,3-keto-aldehydes (7a-c) in good yields as well as byproducts fluorinated acylamides (5a-c).It is proposed that the reactions involve nucleophilic attack by the C-atora and/or N-atom of the enamines on acyl carbon of the fluorinated acyl chlorides.     

1,3-Diphenylpropan-1,3-diamines IX. reaction of α-chlorooxime ethers with α-lithiobenzylamines

Summary The carbanions of the benzylamine derivatives1–4 have been reacted with -chlorooxime ether5 in order to get precursors of 1,3-diphenylpropane-1,3-diamines. Isonitrile1 afforded the expected result, whereas lithiated benzamide2 underwent oxidative dimerization and transmetallated chlorooxime derivative5. Isoxazolidine3 gave the condensation product21 as a mixture of diastereomers; treatment of imine4 led to the desired amine-oxime15 in low yield.Dedicated with warm regards to Prof. Dr.J. Knabe, Saarbrücken, Germany, on the occasion of his 75^th birthday     

Alkaline earth metal–organic frameworks supported by ditopic carboxylates

Hydrothermal reactions of alkaline earth metal nitrates with two ditopic carboxylic acids, trans-1,4-cyclohexanedicarboxylic acid (H₂CDC) and 1,4-phenylenedipropionic acid (H₂PDP), generate two 3-D metal–organic frameworks (MOFs) with empirical formulas [Ca(CDC)(H₂O)₂]·H₂O (1) and [Sr(PDP)(H₂O)] (2), respectively. Compound 1 consists of Ca–COO–H₂O chains cross-linked through the –C₆H₁₀– spacers of the CDC anions, showing slightly open 1-D channels along the crystallographic c axis that accommodate the guest water molecules. Compound 2 exhibits a MOF consisting of wavy 2-D Sr–COO–H₂O nets linked by –CH₂CH₂C₆H₄CH₂CH₂– tethers, and the condensed structure appears to arise from conformational flexibility of the ligand spacer.     

Coordination field analysis of rare earth complexes with triangular symmetry

The calculation of the complex matrixes in odd triangular symmetry was accomplished.The configurations of the coordination unit with various triangular symmetries and different ligand numbers were discussed.On the basis of the double-sphere coordination point-charge (DSCPCF) model,the detailed forms of the DSCPCF parameters Bmk and the expressions of the perturbation matrix elements in triangular field (D3,D3h,D3d) were derived.Thereby,the calculation scheme of coordination field perturbation energy of the rare earth complexes with triangular symmetry was constructed After the calculation scheme was programmed,the Stark energies of the crystalline TbAl3(BO3)4 were calculated The results were considerably close to the experimental values     

1,3-二炔的合成

随着1,3-二炔类化合物在有机合成及功能材料等领域的广泛应用,它的合成引起了广大研究者的关注.本文阐述了1,3-二炔类化合物的合成发展历史,着重综述了近十年来1,3-二炔类化合物的合成发展情况,按原料类别进行介绍,主要包括以末端炔、炔基卤化物、金属炔化物和烯基卤化物等为原料合成1,3-二炔化合物的新成果.文章还分析了一些合成方法在医药领域的应用和重要的反应机理,并总结了该类化合物的合成及未来发展方向.     

1,3-二烷氧基-乙酰丙酮和-丙酮的[1,3] 键迁移重排

1,3-二甲氧基-2-吗啉-N-基戊1-烯-4-酮(11a)的酸水解经证实发生部分重排, 生成1,3-(1a)和1,5-二甲氧基乙酰丙酮(2a)的混合物, 并通过与氰基乙酰胺缩合, 分别形成3-氰基-4-甲氧甲基-5-甲氧基-6-甲基吡啶-2-醇(3a)和3-氰基-4,6-双(甲氧甲基)吡啶-2-醇(4a)加以证实, 前者还转化为维生素B6. 在相应的乙氧基序列中, 除得到1b丶2b丶3b和4b外, 还分离了反向缩合产物3-氰基-4-甲基-5-乙氧基-6-乙氧甲基吡啶-2-醇(5b) . 对Fedoronko 等为1,3-二甲氧基丙酮的重排-水解为丙酮醛提出的烯丙型重排机制提出了质疑. 事实上, 这一重排更可能是一利热过程的[1.3]单键迁移过程和提供了支持的事例.     

(1S,3S)-1,3-二苯基-1,3-丙二胺的合成

以二氯甲烷作溶剂,N-Boc保护的二氢吡唑在六甲基磷酰胺存在下与苯基格氏试剂反应,比较大量地制备了对应的四氢吡唑(4);再由4合成消旋的1,3-二苯基-1,3-丙二胺(1,总收率35%);1经L-二苯甲酰酒石酸盐拆分制得光学纯的(1S,3S)-1,3-二苯基-1,3-丙二胺,其结构经1HNMR确证。     

Natural effectors of β-1,3-glucanases activator of the β-1,3-glucanases of marine mollusks

The capacity of certain extracts of marine invertebrates of the Indian and Pacific Oceans for activating -1,3-glucanases has been detected. It has been shown that an individual compound — swinholide A from the spongeTheonella swinhoei — specifically activates -1,3-glucanases of bivlve mollusks. In the presence of swinholide A both the hydrolysis of laminarin by -1,3-glucanase L-IV fromSpisula sachalinensis and the transglycosylation reaction are accelerated.Pacific Ocean Institute of Bioorganic Chemistry, Far Eastern Branch, Russian Academy of Sciences, Vladivostok. Translated from Khimiya Prirodnykh Soedinenii, Nos. 3,4, pp. 316–320, May–August, 1992.     

1,3—二氨基硫脲的合成研究

１,３－二氨基硫脲（简称ＴＣＨ）是一种重要的有机合成中间体,在一些杂环类医药、农药的合成中有广泛的用途,同时它的一些金属衍生物也具有较大的应用价值。关于其合成方法文献已有报道［１］,且一直受到研究工作者的重视。在几种不同的合成方法中,通常采用的是以二...